1. Field of the Invention
The present invention relates, in general, to RADIO Frequency (“RF”) transparent structures and particularly to RF transparent wall structures comprising polyvinyl chloride (“PVC”) material formed to visually conceal high frequency and broadband antennas and other RF sensitive devices.
2. Relevant Background
High-speed wireless broadband networks and the like continue to grow in popularity and versatility. Consumer interest in such technology has fueled a need to provide uninterrupted service throughout many regions of the United States. Typically wireless services are limited to a relatively short line of sight range from a local antenna, thus the increased demand has fostered a corresponding demand in establishing numerous antenna structures capable of supporting such RF technology. While the demand for such service continues to grow, the tolerance of unsightly antenna structures associated with such a service has been less than forthcoming. To achieve seamless service in many areas, concealed antenna assemblies are placed on rooftops and other structures throughout the United States and other countries. Recent industry consolidation and government bandwidth auctions has limited the number of licensed carriers to a handful of companies, yet their need for local rooftop antennas continues to grow at an exponential rate. These mega-carriers as they are now referred, have recently entered thousands of US cities and rural areas to expand their cellular, broadband and new 4th generation wireless technology networks.
While the wireless industry expands and upgrades existing networks with new site locations, local Township, City and County municipalities serving these communities are becoming tougher on antenna concealment codes and regulations that prohibit antennas from being mounted on buildings and rooftops without a concealment plan that will blend the resulting structure into the environment.
Concealment of antenna structures is typically done to protect the antenna elements from weather or other harsh environments and/or to meet regulatory requirements. In some applications such as the military, antenna structures and the antennas themselves were camouflaged to reduce the likelihood of detection and destruction. While concealment of cellular and other wireless antenna in a civil setting must meet local environmental constraints, the provider of the cellular service faces economic tradeoffs between aesthetically concealing the antennas so as to meet local ordinances and codes while minimizing the detrimental effects of the concealment assembly on signal strength and the functionality of the antenna.
Prior antenna concealment assemblies have generally been customized structures typically composed of Fiberglass, Fiberglass Reinforced Plastic (“FRP”), Polyurethane Foam, ABS Plastic and/or other composite material. Them materials have offered a reasonable degree of structural integrity and strength as well as reasonable degree of RF transparency for lower frequency cellular applications. Such customized structures and material choices, when implemented on a pervasive scale, are however, less feasible for higher spectrum broadband and satellite applications due to extreme RF transparency requirements.
Architectural and engineering firms typically design custom wireless rooftop sites using steel or similar metallic substances for mating with ballasted frames or structural roof connections from the building. From these connections a frame is constructed to house various antennas. A custom concealment assembly's frame and skin are normally thereafter attached to this steel antenna frame to conceal the antennas. As mentioned, the structure of these existing concealment products, such as the skeleton and external panels, are typically concealed with relatively thick fiberglass or FRP sheathing products.
As demand for cellular and wireless capability continues to grow, so to does the need to install and conceal additional cellular and wireless antennas. A need exists, therefore, to conceal these antennas with a standardized and cost effective concealment assembly that is both economical to produce and install as well as ultra transparent to higher RF used for data rich transmissions . These and other problems recognized in the prior art are addressed by the present invention.